Cyclocondensation Reaction Research Articles

Synthesis of Hetaryl Substituted Pyrazolo[3,4-b]Quinolinone Systems by Multicomponent Cyclocondensation Reaction

In this study, the synthesis of pyrazolo[3,4-b]quinolinone compounds was carried out via one-pot three-component reactions. These reactions proceed as domino processes, making them easier to occur than the conventional multistep organic reactions. By employing this method, new organic molecules can be synthesized in a single step, using minimal time and number of trials. In the first phase of this two-step study, heteroaromatic carbaldehydes (quinoline-8-carboxaldehyde and quinoline-4-carboxaldehyde) were prepared to be used as substrates in subsequent reactions by oxidation of 8-methylquinoline and 4-methylquinoline with selenium dioxide, a mild oxidant. In the second step, heteroaromatic carbaldehyde reacted with aminopyrazole and dimedone in anhydrous ethanol by one-pot multicomponent condensation method to synthesize six new compounds with heteryl-substituted pyrazolo[3,4-b]quinolinone ring system. The crude products were obtained in excellent yields and further purified by crystallization. The structures of the compounds, which were found to be completely pure as a result of chromatographic studies, were elucidated by spectroscopic methods and elemental analysis.

Screening of synthesized perimidine compounds for the assessment of antimicrobial potential: in-vitro and in-silico molecular docking and molecular dynamics simulation studies

Presently, antimicrobial resistance is a major and worldwide concern due to high rate of mutation in microorganisms, widespread use, lack of efficacy of drugs, and low drug discovery rate. Considering the importance of N-heterocycles as antibiotics, perimidine derivatives 3(a–v) have been synthesized via cyclocondensation reaction of 1,8-diaminonaphthalene and aryl aldehydes. Further, the synthesized perimidines 3(a–v) were screened as potent antimicrobial agents via in-vitro, in-silico, ADME and MD simulation studies. All 22 derivatives 3(a–v) were studied against two-gram +ve (E. coli and P. aeruginosa), two-gram −ve (S. aureus and B. subtilis), and two fungal (A. niger and S. cerevisiae) strains using ciprofloxacin and fluconazole as reference drugs. The in-vitro study results showed that compounds 3e, 3h, 3l, and 3m were the most potent against S. aureus and 3(a–d), 3(g–i), and 3s were the most active against B. subtilis as compared to the standard. Furthermore, molecular docking studies were performed against Dihydrofolate reductase (PDB Id: 3SRW) from S. aureus, DNA gyrase (PDB Id: 4DUH) from E. coli, and ERG11 gene (PDB Id: 4LXJ). Compounds 3f, 3f/3m, and 3o were found to bind efficiently with the highest binding energy − 10.6, − 9.6, and − 11.3kcal/mol depicting the potential inhibitor of 3SRW, 4DUH, and 4LXJ receptor protein, respectively. The drug-likeness properties of compounds were studied using SwissADME program. To further validate these findings, molecular dynamics simulations were conducted to evaluate their binding stability. From simulation studies, it was observed that all the shortlisted compounds displayed stable binding within the active site of the selected proteins.Graphical abstract

Synthesis of New Heterocyclic Derivatives from 4-(3, 5-Dimethyl-1-phenyl-1H-pyrazol-4-ylazo)- benzoic acid

In this work pyrazolin derivatives were prepared from the diazonium chloride salt of 4-aminobenzoic acid. Azo compounds were prepared from the reaction of an ethanolic solution of sodium acetate and calculated amount of active methylene compound namely, acetyl acetone to obtain the corresponding hydrazono derivative (1). Cyclocondensation reaction of compounds (1) with hydrazine hydrate and phenyl hydrazine in boiling ethanol affording the corresponding pyrazoline-5-one derivatives of 4-aminobenzoic acid (2,3). Then compound (3) was reacted with thionyl chloride to give the corresponding acid chloride derivative(4), followed by conversion into the corresponding acid hydrazide derivative (5) carboxylic acid thiosemicarbazide (11), esters (14,15), thioesters (16,17) and amides (18,19), when treated hydrazine hydrate, thiosemicarbazide, alcohols, alkylthiol and secondary amines in dry refluxing benzene; respectively. Schiff's bases (6-8) were prepared by refluxing of compound (5) with different aldehydes and ketons, then two compounds from the Schiff's bases were cyclized with ?-mercapto acetic acid to give (9 and 10). Furthermore, 1,2,4-triazole derivative (12) have been also prepared by refluxing thiosemicarbazide derivative with sodium hydroxide solution (4%) followed acidification of the result using (10%)hydrolic acid. Moreover, a thiadiazole derivative (13) has been prepared by treatment of thiosemicarbazide derivative with concentrated sulfuric acid as cyclyzing agent. Finally, oxadiazole derivative (20) has prepared by condensation of its acid hydrazide derivative with carbon disulfide in basic medium.

Designing highly porous three-dimensional triazine-bearing covalent organic polymers as prominent adsorbents of carbon dioxide and iodine

A new class of triazine-containing covalent organic porous polymers TCOP1-3 were made using a versatile one-pot [3 + 2] cyclocondensation reaction revealing remarkable robustness as proven by their thermal stability which disclosed a 10 % weight loss temperature ≥400 °C. Investigation of the intrinsic microporosity properties of TCOP1-3 using nitrogen adsorption experiments disclosed salient Brunauer–Emmett–Teller (BET) surface areas ranging from 725 to 932 m2 g−1 with average pore volumes in the range of 0.52–0.65 cm3 g−1. TCOP1-3 exhibited high CO2 uptakes attaining 120 mg g−1 at 273K and low pressure whereas iodine capture tests demonstrated significant results achieving a maximum adsorption of 4.02 g g−1. Recycling experiments confirmed the potential for these polymers to be restored even after a multitude of concurrent iodine adsorption-desorption cycles.

Exploring Benzo[b][1,4]Thiazine Derivatives: Multitarget Inhibition, Structure–Activity Relationship, Molecular Docking, and ADMET Analysis

AbstractA series of benzothiazine derivatives (1–17) were synthesized via an intermolecular cyclocondensation reaction involving 2‐aminothiophenol (i) and substituted phenacyl bromide (ii). Structural elucidation of these synthetic derivatives utilized EI–MS, HR‐EIMS, 1H NMR, and 13C NMR spectroscopic techniques. The synthesized analogs were evaluated against key enzyme targets (acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α‐glucosidase (α‐Glu)) and tested for cytotoxicity against various cancer cell lines. Six compounds were selected based on their inhibition profiles, exhibiting significant inhibitory potential against enzymes. In silico studies corroborated the observed inhibitory activities, aligning closely with experimental outcomes. Additionally, an ADME/T study provided insights into pharmacokinetic and safety profiles, identifying promising candidates for future drug development efforts.

Effect of microwave irradiation on the synthesis of zeolite with ferrierite structure: Study of acid and catalytic properties

Ferrierite zeolite (FER) was synthesized under microwave conditions while varying the microwave exposure time from 6 to 12 h. For comparison, commercial FER and a FER zeolite synthesized by the conventional hydrothermal synthesis (72 h) were studied. The structure, texture, and acidic properties of the samples were investigated by XRD, low-temperature N2 adsorption, ICP-AES, SEM, and DRIFT spectroscopy using adsorption of CO, CD3CN and pyridine as probe molecules. The catalytic characteristics of the obtained zeolites were studied in the cyclocondensation reaction of 1,2-phenylenediamine and acetone to produce 1,5-benzodiazepine. The activity of the zeolites in this reaction was found to increase with increasing microwave exposure time. The FER-MW sample synthesized in 12 h showed the best results.

Chemo- and regioselective controlled synthesis and thermal analysis characterization of trifluoromethyl polypyrazoles

This study details the chemo- and regioselective synthesis and spectroscopic and thermal analysis characterization of trifluoromethyl bipyrazoles and polypyrazoles by stepwise N-alkylation of pyrazoles using (E)-4-(amino)-5-bromo-1,1,1-trifluoro-but-3-en-2-ones (5-bromo enaminones), followed by cyclocondensation of the enaminone moiety with hydrazines. A mechanism for the cyclocondensation reaction was proposed. Sixteen new methylene-bridged bipyrazoles and polypyrazole chains with up to five pyrazole units were achieved at very good yields. All the compounds were characterized by 1H and 13C NMR, and the 1,3-regiochemistry was evidenced by single-crystal X-ray diffraction. The polypyrazoles’ thermal behavior was elucidated by thermogravimetric analysis and differential scanning calorimetry. It is suggested that at approximately 300°C the polypyrazoles thermally decompose independent of the number of repeating units. The second and third heating/cooling cycles of the differential scanning calorimetry indicate that the majority of the polypyrazoles are amorphous materials, with glass transition values that can be tuned by the number of repeating units in the polymeric chain and the type of linkage between the pyrazole rings.

Microwave-assisted green synthesis and molecular docking study of some new 4-thiazolidinone derivatives as possible bioactive agents

We have developed an economical and environmentally friendly microwave-assisted efficient method for the synthesis of a series of new 4-oxo-thiazolidine derivatives (4a-d). The method involves microwave irradiated cyclocondensation reaction of Schiff bases (3a-d) and thioglycolic acid in drug master file (DMF). 4-oxo-thiazolidine derivatives (4a-d) was also synthe 4-Oxo-Thiazolidine derivatives were also synthesized by conventional heating procedures and consequence were Compared with Microwave assisted green method. The results suggest that microwave-assisted syntheses lead to higher yields within very short reaction times. Antimicrobial screening of all the synthesized compounds was carried out using Gram-positive strains Staphylococcus aureus and Gram-negative strain encompassing Escherichia coli, Proteus vulgaris, and Salmonella typhi. The results were compared with the standard drug chloramphenicol. All the synthesized compounds were subsequently examined using molecular docking experiments against peptide deformylase (PDB ID: 1G2A), which evaluates the binding interaction of ligands with enzyme active sites.. KEYWORDS :Microwave irradiation, Thiazolidinone, Molecular docking, Peptide deformylase, Antimicrobial screening.

Exploring Cyclopentannulation as an Effective Synthetic Tool to Design Polycyclic Aromatic Hydrocarbon AIEgens for Bioimaging.

Synthesis of various polycyclic aromatic hydrocarbons (PAHs) from a palladium-catalyzed [3 + 2] cyclocondensation reaction is reported herein. The design strategy consisted of reacting the sterically hindered 1,2-bis(3,5-ditert-butylphenyl)acetylene 2 with myriad brominated anthracene and pyrene surrogates, resulting in the formation of target molecules MCP1-2 and DCP1-3, which exhibited excellent solubility in commonly used organic solvents and unveiled prominent aggregation-induced emission (AIE) characteristics in tetrahydrofuran and water solvent mixtures. Calculations using density functional theory (DFT) were utilized to validate both the contorted structures of the target molecules and their electronic conjugation featuring HOMO-LUMO band gaps (ΔE) in the range of ∼2.88 to 2.97 eV for the monocylopentannulated PAHs MCP1-2, and between ∼2.23 to 2.41 eV for the dicyclopentannulated PAHs DCP1-3. Furthermore, the biomedical features of DCP2 were investigated in cell-imaging experiments employing the RAW 264.7 macrophage cell line as a model system showing a high biocompatibility for DCP2, thus paving the way for its potential application in bioimaging. These findings underscore the significance of the target compounds as prominent AIEgens with exceptional photophysical properties and biocompatibility, therefore promoting them as valuable tools for bioimaging applications.

Synthesis, characterization, cytotoxicity, and antiviral activity of new coumarin analogues against coronavirus

Coronaviruses have emerged as a global health challenge, with the recent outbreak of SARS-CoV-2 affecting more than 600 million individuals worldwide. While vaccination remains a central preventive approach, addressing SARS-CoV-2 involves antiviral drugs, monoclonal antibodies, and corticosteroids. Research indicates that coumarin exhibits potent antiviral properties. Therefore, this study aimed to investigate the antiviral properties of newly synthesized coumarin analogues (NCA) against coronaviruses. The study involved the synthesis of NCAs through esterification, hydrazination, imination, and cyclo-condensation reactions, followed by their characterization using FTIR, NMR, and Mass Spectrometry. Cell viability analysis was conducted using HEK-293 cells, and the viral replication inhibition activity of NCAs against OC43 was assessed using plaque assays. The antiviral activity of NCAs against the Infectious Bronchitis Virus (IBV) was evaluated based on mortality rate, lesion development, and viral RNA load suppression. The study successfully synthesized NCAs and elucidated their structures. The viral plaque assay demonstrated the ability of NCAs to effectively inhibit viral replication. Analysis of viral RNA by qRTPCR confirmed a decrease in OC43 viral load following NCA treatment. Immunofluorescence assays also showed a reduction in SARS-CoV-2 infection in the presence of NCAs. Evaluation of cytotoxicity using HEK-293 cells indicated that NCAs exhibited a favourable safety profile while effectively inhibiting IBV viral replication. These findings highlight the promising antiviral activities of NCAs against coronavirus replication and infection.

Facile Synthesis of Donor-Acceptor Heterocycloarenes Based on Pyrazine Derivatives Possessing Intriguing Iodide Ion Capture Properties.

Donor-acceptor (D-A) conjugated systems have been extensively investigated and play important roles in organic electronics. Incorporating D-A structures into (hetero)cycloarenes endows them tunable electronic properties, while the well-defined cavity remains. However, the synthetic complexity of introducing electron-acceptor moieties into (hetero)cycloarenes limits their development and applications. In this paper, the first family of electronically tunable D-A heterocycloarenes (DAHCn, n = 1-5) based on pyrazine derivatives was facilely synthesized through cyclocondensation reaction from a tetraketone-functionalized heterocycloarene precursor prepared using the ketal-protection strategy. The effect of expanded conjugation and the inserted electron-withdrawing group on the electronic structures of the D-A heterocycloarenes was studied systematically by X-ray crystallographic analysis, various spectroscopic measurements, and theoretical calculations. Interestingly, the presence of an electron-withdrawing group polarizes the inner C(sp2)-H and significantly increases the binding affinities of D-A heterocycloarenes to the iodide anion. Meanwhile, the anion affinity can be further modulated by the type of attached substituents and the distance of polarization. More importantly, the dicyanopyrazine derivative DAHC3 shows the highest binding strength to the iodide ion as a 2:1 sandwich complex (log β2 = 12.3 and ΔG = -69.1 kJ mol-1), which is the strongest iodide receptor using C(sp2)-H hydrogen bonding interactions reported to date. Our finding provides a new strategy to design and synthesize D-A heterocycloarenes and strong anion receptors.

Porous Organic Polymers (POPs) Based on Acridone as Heterogeneous Photocatalysts for Oxidative Dimerization and Cyclocondensation Reactions

AbstractPorous organic polymers (POPs) are emergent tailor‐made materials, which can be accessed by covalent polymerization of diligently designed molecular building blocks in a bottom‐up fashion. Acridone, a well‐known chromophore that undergoes intersystem crossing (ISC) with near‐unity quantum yield akin to benzophenone, was structurally elaborated into a building block and subjected to Friedel‐Crafts polyalkylation to afford a series of POPs, namely, Ac‐MePOP, Ac‐OMePOP, and Ac‐CBPOP. These POPs exhibit remarkable porosity and significant absorption in the visible region. Of the three polymers, Ac‐CBPOP with the highest BET surface area of ca. 1027 m2/g is shown to serve as an excellent heterogeneous photocatalyst for visible light‐mediated oxidative transformations, that is, oxidative coupling of benzylamines to imines and cyclocondensation of o‐phenylenediamines with aldehydes to benzimidazoles under oxygen atmosphere. It is further shown that Ac‐CBPOP can be reused for several reaction cycles without any loss of catalytic activity with its stability intact. Mechanistic studies show that 1O2 serves as the key reactive oxygen species, formed by the energy transfer from Ac‐CBPOP to 3O2, in the photocatalytic oxidation reactions. The results demonstrate the development of stable photocatalytic POP materials with tailor‐made properties by a bottom‐up covalent polymerization of programmed molecular building blocks.

Engineered anion π complex with non-covalent π interaction system and its catalytic ability on the cyclocondensation reaction of 2-aminobenzimidazole, aryl aldehyde and ethyl acetoacetate

The specific-task engineered anion π complex namely N-sulfopyridin-1-ium monozinc (II) trichloride {[NSPy]ZnCl3} was used as a catalyst for the cyclocondensation reaction of 2-aminobenzimidazole, aryl aldehyde and ethyl acetoacetate with interesting mechanism to give 4H-pyrimido[2,1-b] benzimidazoles in high yields and short reaction times. The designed complex with non-covalent π interaction between [Pyridine–SO3H]Cl and zinc (II) can be acted as multipurpose and efficient catalyst for the preparation of the expected products.

Comparative investigation on composting and pyrolysis of swine manure: Heavy metals transformation, nitrogen immobilization and integrated environmental risk assessment

Harmless treatment of livestock manure has been a pressing issue due to its contamination of heavy metals and volatilization of nitrogen(N)-containing components during processing. In this paper, the chemical species transformation, leaching characteristics of Cr, Mn, Zn, Cu and conversion of amine N and inorganic N during composting and pyrolysis of swine manure (400°C, 500°C, 600°C and 700°C) were comparatively investigated, and their integrated environmental risk (η) was assessed. According to the ultimate and proximate analysis, pyrolyzed char exhibited better aromaticity and richer functional groups compared with that of compost; Cr, Mn, Zn, Cu were transformed into more stable residual states (F3+F4), and better inhibition of leaching in simulated landfill experiments was shown than compost. However, deamination and cyclocondensation reactions under higher pyrolysis temperatures resulted in N escaping in the form of NH3 and HCN. Considering various pollution coefficients, the integrated ecological risk was reduced by 59.24 % after 600°C pyrolysis, which is the optimal condition for the minimization of the risk of heavy metal toxicity and N volatilization among all the compost and pyrolysis process.

Novel benzothiazole-pyrazoline-styrene hybrid for ultrasensitive detection of Hg(II) ions: Synthesis and chemosensor evaluation.

Water pollution has become a serious issue, and mercury(II) ion (Hg(II)) is highly toxic even at low concentrations. Therefore, Hg(II) concentration should be strictly monitored. This study evaluated pyrazoline compounds as fluorescence chemosensor agents for Hg(II) detection. These compounds were prepared from vanillin via etherification, Claisen-Schmidt, and cyclocondensation reactions, to yield benzothiazole-pyrazoline-styrene hybrid compounds. The hybrid compound without styrene was successfully synthesized in 97.70% yield with limit of detection (LoD) and limit of quantification (LoQ) values of 323.5 and 1078 μM, respectively. Conversely, the hybrid compound was produced in 97.29% yield with the LoD and LoQ values of 8.94 and 29.79 nM, respectively. Further spectroscopic investigations revealed that Hg(II) ions can either chelate with three nitrogen of pyridine, pyrazoline, and benzothiazole structures or two oxygen of vanillin and styrene. Furthermore, the hybrid compound was successfully applied in the direct quantification of Hg(II) ions in tap and underground water samples with a validity of 91.63% and 86.08%, respectively, compared with mercury analyzer measurement. The regeneration of pyrazoline was also easily achieved via the addition of an ethylenediaminetetraacetic acid solution. These findings show the promising application of the benzothiazole-pyrazoline-styrene hybrid compound for Hg(II) monitoring in real environmental samples.

Synthesis and characterization of alumina supported molybdosilicic acid (SiMo12/Al2O3): Efficient solid acid catalyst for the synthesis of pyranopyrazole derivatives

A series of highly reusable heterogeneous catalysts (10-40 wt.% SiMo12/Al2O3), consisting of molybdosilicic acid (SiMo12) impregnated on alumina (Al2O3) support was synthesized by the wetness impregnation method. The physicochemical properties of synthesized catalyst were studied using FT-IR, XRD, SEM, EDX, TEM, BET and TG-DTA analysis techniques. The study proves that the synthesized SiMo12 catalyst efficiently incorporated on the surface of Al2O3. The catalytic activity of prepared catalyst was investigated for the synthesis of pyranopyrazole(6-amino-4-phenyl-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5carbonitrile) via cyclocondensation reaction of aldehydes, malononitrile, hydrazine hydrate and ethyl-acetoacetate under solvent-free conditions. Among different catalysts, 30% SiMo12 supported on to Al2O3 showed the highest catalytic activity. High yield, shorter reaction time, operational simplicity, solvent-free conditions and reusability of the catalyst are the distinct features of this protocol.

Design and Synthesis of Polyheterocyclic Compounds Containing Pyrazolopyridopyrimidine Nucleus with Antimicrobial Activities.

This study reports the design, synthesis, and antibacterial evaluation of a library of novel polyheterocyclic derivatives featuring a unique fused pyrimidopyridopyrazole moiety. A cyclocondensation reaction between an amino-pyrazolopyridopyrimidine precursor and malonates afforded a series of pyrimidopyridopyrazolopyrimidine derivatives. Further diversification was achieved through nucleophilic cyclocondensation, yielding a collection of complex polyheterocyclic systems encompassing various ring structures. All synthesized compounds were rigorously characterized using spectroscopic techniques and elemental analysis. The antibacterial activity of the newly synthesized compounds was assessed against a panel of Gram-positive and Gram-negative bacteria. Notably, several compounds exhibited promising antibacterial activity, highlighting their potential as leads for the development of novel antibiotics.

Enhancement of the sensitivity of chalcone derived from vanillin as chemosensor agents for Hg(II) ions through cyclization reaction with arylhydrazine

Water pollution is currently a major problem worldwide. Given its detrimental effects on health, Hg(II) is considered an extremely hazardous heavy metal contaminant, even at low doses. Heterocyclic compounds have been thoroughly evaluated as the chemosensor agents for Hg(II) detection. However, they suffer from poor sensitivity. In this study, we prepared two fluorescence chemosensor agents from vanillin via several steps, i.e., etherification, Claisen–Schmidt, and cyclocondensation reactions to yield N-phenyl- and N-pyridine-pyrazoline compounds. Products characterization was accomplished via spectroscopic techniques. Chalcone, N-phenyl-, and N-pyridine-pyrazoline derivatives were successfully obtained at 87.04%, 90.91%, and 91.73% yields, with limits of detection of 156,840, 65.810, and 161.011 nM, respectively. These results show that the conversion of chalcone to pyrazoline structure improved the sensitivity for Hg(II) detection at the nanomolar level, which is 2384 times lower than that for chalcone. Further spectroscopic investigations through Job's plot, Fourier-transform infrared spectroscopy, and proton-nuclear magnetic resonance analyses revealed that Hg(II) ions were chelated with two nitrogen atoms of pyrazoline. Thus, this phenomenon can explain the considerable sensitivity enhancement for Hg(II) detection. N-Phenyl-pyrazoline is the more sensitive chemosensor to Hg(II) compared with N-pyridine-pyrazoline because the more nitrogen groups in the binding site, the less selective and sensitive the compound. This finding is also supported by the higher binding constant value of N-phenyl-pyrazoline (9.416 × 102 mol−1) than N-pyridine-pyrazoline (1.771 × 102 mol−1). Furthermore, N-phenyl-pyrazoline can be applied in the direct quantification of Hg(II) in tap and groundwater samples with a validity parameter in a range of 80.97%–103.54%.

Promising CO2 Capture and Effective Iodine Adsorption of Hyper-Cross-Linked Conjugated Porous Organic Polymers Prepared from a Cyclopentannulation Reaction.

Three novel conjugated porous organic polymers, denoted as C-POP1-3 and which consist of alternating pyrene cores with various contorted fluorene surrogates, were successfully synthesized from a versatile one-pot palladium-catalyzed [3+2] cyclocondensation reaction. The resulting polymers were obtained in excellent yields and displayed weight-average molecular weights (Mw) ranging from 12.2 to 20.2 kg/mol with polydispersity indices (Mw/Mn) ranging between 1.8 and 2.4, suggesting that the molecular masses are narrowly distributed and thus implying homogeneous polymer chains. Thermal stability exploration of C-POP1-3 by thermogravimetric analysis (TGA) revealed an impressive robustness with a 10% weight reduction temperature attaining 485 °C. Investigation of the inherent microporosity properties of C-POP1-3 via nitrogen adsorption experiments using Brunauer-Emmett-Teller (BET) theory discloses their surface areas which reach up to 560 m2 g-1 and pore volumes averaging 0.47 cm3 g-1. The target conjugated polymers were explored as adsorbents disclosing a maximum carbon dioxide adsorption of 83.0 mg g-1 at 273 K and low pressure for C-POP1, whereas iodine sorption tests portrayed prominent outcomes, notably for C-POP3 which proved to owe a strong affinity toward the hitherto mentioned halogen by achieving a maximum adsorption of 2220 mg g-1. Additionally, recyclability experiments confirmed the possibility to regenerate the polymers' adsorption capabilities even after seven consecutive cycles of adsorption-desorption cycles, which qualify them as auspicious iodine adsorbents.

Proflavine (PFH+): as a photosensitizer (PS) biocatalyst for the visible-light-induced synthesis of pyrano [2,3-d] pyrimidine scaffolds.

A sustainable methodology for the synthesis of pyrano [2,3-d] pyrimidine scaffolds have been developed, employing the Knoevenagel-Michael tandem cyclocondensation reaction of barbituric acid/1,3-dimethylbarbituric acid, malononitrile, and aryl aldehydes. This study elucidates the advancement of a sustainable and environmentally conscious approach to synthesizing this category of chemical compounds. In the present investigation, a novel photosensitizer comprising proflavine (PFH+) bio-photocatalyst was employed in an aqueous medium, subjected to air atmosphere at room temperature, and stimulated by a blue-light-emitting diode (LED) to harness renewable energy. The fundamental objective of this initiative is to utilize a photosensitizer (PS) biocatalyst that has been recently developed, can be conveniently acquired, and is priced affordably. The proflavine (PFH+) photocatalyst, demonstrates the ability to initiate photoinduced-electron transfer (PET) through exposure to visible light. This property endows the photocatalyst with a practical and efficient method of achieving high effectiveness, energy efficiency, and environmentally friendly outcomes. The current research endeavor has the objective of examining the turnover number (TON) and turnover frequency (TOF) pertaining to pyrano [2,3-d] pyrimidine scaffolds. Moreover, it has been validated that cyclization at the gram-scale is a feasible approach that can be employed in various industrial settings.